This retrospective cohort study evaluated annual marginal bone level change and identified patient-, implant-, and treatment-level determinants in posterior maxillary implants.

Records of patients who received posterior maxillary implants between 2014 and 2024 were retrospectively reviewed. Marginal bone level changes were measured on standardized periapical radiographs obtained at implant placement and at the latest follow-up. Annual marginal bone change (mm/year) was calculated to account for heterogeneous follow-up durations. Multivariable generalized estimating equation models with robust standard errors were used to evaluate independent associations while accounting for clustering of multiple implants within patients.

A total of 115 implants placed in 78 patients were included, with a mean follow-up of 5.25 ± 2.49 years. Mean annual marginal bone level change was −0.04 ± 0.28 mm/year. After multivariable adjustment, free-hand surgery (β = 0.179 mm/year; 95% CI 0.039, 0.319) and static guided surgery (β = 0.221 mm/year; 95% CI 0.092, 0.350) were associated with lower annual marginal bone loss than navigation-assisted surgery. In contrast, osteotome and sinus augmentation procedures were associated with greater annual marginal bone loss compared with implants placed without adjunctive procedures (β = −0.176 mm/year; 95% CI −0.347, −0.006) (all p < 0.05).

Marginal bone loss in the posterior maxilla was modest during long-term follow-up. Surgical methods and adjunctive procedures were associated with annual marginal bone level change in this cohort. However, given the observational nature of the study, these findings should be interpreted as exploratory associations rather than clinically predictive factors or definitive evidence to support specific treatment choices.